StructSight 🔍

C++ Memory Layout Visualizer for VS Code

A project by IEEE Computer Society BMSIT&M
Developed by Atul K M

StructSight is a powerful VS Code extension that provides real-time visualization of C++ struct and class memory layouts. Get instant insights into memory padding, alignment, vtable layouts, and optimization opportunities - all while you code.

✨ Features

📊 Interactive Memory Visualization

• Hover over struct/class definitions to see memory layout summaries
• Open detailed webview with complete memory map
• Visual representation of members, padding, and alignment
• Color-coded padding regions with explanations

🎯 Cache Line Analysis

• Visualize 64-byte cache line boundaries
• Detect members spanning multiple cache lines
• Optimize for cache-friendly data structures

🚀 Optimization Suggestions

• Automatic detection of excessive padding
• Suggested member reordering for size reduction
• "Can save X bytes" insights with confidence scores
• One-click refactoring to apply optimizations

🔧 Multi-Architecture Support

• Switch between 32-bit (x86) and 64-bit (x64) architectures
• Compiler-specific layout rules (GCC, Clang, MSVC)
• See how your structs behave across different platforms

🎨 Virtual Table Visualization

• Detect polymorphic classes automatically
• Visualize vtable pointer placement
• List all virtual functions
• Handle multiple inheritance scenarios

📸 Screenshots

Hover Information

Detailed Memory Layout

Optimization Suggestions

🚀 Getting Started

Installation

Install from the VS Code Marketplace:

1. Open VS Code
2. Go to Extensions (Ctrl+Shift+X)
3. Search for "StructSight"
4. Click Install

Prerequisites

Windows:

• LLVM/Clang development libraries (pre-built binaries included)
• Visual Studio 2019 or later (for building from source)

Linux:

sudo apt-get install llvm-14-dev libclang-14-dev clang-14

macOS:

brew install llvm

Usage

1. Hover Analysis: Hover over any struct or class keyword to see a quick summary
2. Detailed View: Click "Show Detailed Layout" or use command StructSight: Show Memory Layout
3. Apply Optimizations: Click the "Apply Reordering" button in the webview or use VS Code's Quick Fix (Ctrl+.)

⚙️ Configuration

Configure StructSight through VS Code settings:

{
  "structsight.architecture": "x64",          // "x86" or "x64"
  "structsight.compiler": "clang",            // "gcc", "clang", or "msvc"
  "structsight.cacheLineSize": 64,            // Cache line size in bytes
  "structsight.showPaddingBytes": true,       // Highlight padding
  "structsight.showOptimizationHints": true,  // Show optimization suggestions
  "structsight.enableHoverInfo": true         // Enable hover provider
}

🎯 Examples

Before Optimization

struct BadLayout {
    char a;      // 1 byte
    int b;       // 4 bytes (3 bytes padding before)
    char c;      // 1 byte
    double d;    // 8 bytes (7 bytes padding before)
};
// Total: 24 bytes (10 bytes padding!)

After Optimization (suggested by StructSight)

struct GoodLayout {
    double d;    // 8 bytes
    int b;       // 4 bytes
    char a;      // 1 byte
    char c;      // 1 byte
    // 2 bytes tail padding
};
// Total: 16 bytes (only 2 bytes padding) - 33% size reduction!

🏗️ Architecture

StructSight combines the power of Clang's LibTooling with VS Code's extension API:

• C++ Analysis Engine: Uses Clang AST to parse C++ code with compiler accuracy
• Native Node.js Addon: Exposes C++ analysis to TypeScript via N-API
• TypeScript Extension: Provides VS Code integration and UI
• React Webview: Interactive visualization of memory layouts

🤝 Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

Development Setup

# Clone the repository
git clone https://github.com/yourusername/structsight.git
cd structsight

# Install dependencies
npm run install:all

# Build native addon
npm run build:native

# Build extension
npm run build:extension

# Run in development mode
code .
# Press F5 to launch extension development host

📝 License

MIT License - see LICENSE for details

👥 Author & Organization

Developed by: Atul K M
Organization: IEEE Computer Society - BMSIT&M
Project Type: Educational Tool for C++ Developers

About IEEE CS BMSIT&M

The IEEE Computer Society chapter at BMS Institute of Technology & Management is dedicated to fostering innovation and technical excellence in computer science and software engineering.

🙏 Acknowledgments

• Built with Clang's LibTooling
• Inspired by the need for better C++ memory layout understanding
• Thanks to the VS Code extension API team
• Special thanks to IEEE Computer Society BMSIT&M for supporting this project

🐛 Issues & Feature Requests

Found a bug or have a feature request? Please open an issue!

📚 Resources

• C++ Memory Layout Guide
• Optimization Best Practices
• API Documentation
• Publishing Guide

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Made with ❤️ by IEEE CS BMSIT&M for C++ developers who care about performance